1. Field of the Invention
The invention relates to catalysis, and particularly to hydrocarbon hydroprocessing catalysts, such as those utilized to catalyze the reaction of hydrogen with organo-sulfur, organo-nitrogen, organo-metallic, and asphaltene compounds. More particularly this invention is directed to a process for hydrodesulfurizing and hydrodenitrogenating heavy hydrocarbon liquids.
2. Description of the Prior Art
In the refining of hydrocarbon oils, it is often desirable to subject the hydrocarbon oil to catalytic hydroprocessing. During hydroprocessing, particulate catalysts are utilized to promote reactions such as desulfurization, denitrogenation, demetallization and/or conversion of asphaltene compounds. This is accomplished by contacting the particulate catalyst with a feedstock, such as a residual petroleum oil fraction, under conditions of elevated temperature and pressure and in the presence of hydrogen so that the sulfur components are converted to hydrogen sulfide, nitrogen components to ammonia, asphaltenes to molecules having increased hydrogen to carbon (H/C) ratios and contaminant metal components to components capable of being deposited on the catalyst. Typically, hydroprocessing is employed to reduce the concentration of nitrogen and sulfur in feedstocks so as to produce hydrocarbons which, when eventually combusted, result in reduced air pollutants of the forms NO.sub.x and SO.sub.x. Reducing the concentration of nitrogen and metals is also desirable to protect other refining catalysts, such as hydrocracking catalysts, which deactivate in the presence of nitrogen and contaminant metals.
A typical hydroprocessing catalyst contains hydrogenation metals on a porous refractory oxide support. Hydrogenation metals usually include Group VIB and/or Group VIII active metal components supported on amorphous refractory oxide supports such as alumina. The porous refractory oxide supports have a wide variety of pore sizes and pore size distributions. Also, "acidifying" agents, such as phosphorus components, are commonly impregnated onto the catalyst to improve its activity by increasing its acidity. Other means of increasing the acidity of the catalyst have included incorporating zeolite materials into the amorphous refractory oxide support.
Despite the high hydroprocessing activity of the catalysts of the prior art, catalysts of yet higher activities are still being sought. The higher the activity of the catalyst, the lower the reactor temperature required to obtain a product of given nitrogen, sulfur, asphaltene, or metal content from the feedstock. The lower the reaction temperature, the lower the expense of hydroprocessing a given unit of feedstock due to the savings in process heat requirements.
A common problem with hydroprocessing catalysts containing acidifying components is the hydrolysis of such components either prior to or during processing of the hydrocarbon. Hydrolysis results in the loss of the acidifying component from the catalyst and consequently the catalyst activity is decreased. Also, as the lost acidic materials from the catalyst pass downstream, the refinery metallurgy may be attacked and damaged by corrosion.
Accordingly, it is a major object of this invention to provide a hydroprocessing catalyst having non-hydroyzable acidifying components, and more particularly to provide a catalyst containing a non-hydrolyzable acidifying component.
Another object of the invention is to provide a method for hydroprocessing a hydrocarbon feedstock with a particulate catalyst containing a non-hydrolyzable acidifying component.
It is a further object of the invention to provide a catalytic hydroprocessing method for a hydrocarbon residuum feedstock wherein the catalyst contains a support matrix having amorphous refractory oxides of controlled pore size interspersed with non-hydrolyzable acidifying components.
Another object of the invention is to provide a process for removing organo-nitrogen and/or organo-sulfur compounds from a residuum hydrocarbon oil by contacting the oil with a catalyst having non-hydrolyzable acidifying components and amorphous refractory oxides.
These and other objects and advantages of the invention will become apparent from the following description.